Expansible shaft



Dec. 1, 1936. G. UNDBQM 2,062,421-

' EXPANSIBLE SHAFT Filed July 27, 1935 2 Sheets-Sheef.

Dec. 1, 1936. C G, iNDBOM A 2,062,421

EXPANS IBLE SI- IAFT Filed July 27, 1935 2 Shee'tS-Sheekt 2 INVENTOR.

Patented Dec. 1, 1936 EXPANSIBLE SHAFT Carl G. Lindbom, Dover, N. H., assignor to U. P. M.Kidder Press Co., Inc., Dover, N. H., a corporation of Delaware Application July 27, 1935, Serial No. 33,507

12 Claims.

This invention relates to expansible shafts and more particularly to such shafts used in the winding or rewinding of Webs of sheet material such as paper. Suchwebs are wound on a core, ordinarily a tube of cardboard or other soft material having an inside diameter slightly larger than the shaft of the winding mechanism so that it may readily be slipped on and off of said shaft. Heretofore various devices for engaging or clutching the ends of the core have been employed to insure rotation of the core with the winding shaft. Such devices are inadequate if the core is shorter than theshaft or if a number of short cores for simultaneously winding a number of ribbons are mounted on a single winding shaft. Accordingly various types of expansible shafts have been employed for such cores, generally expanded and contracted by mechanical means, making provision for` insuring a rotation of the core with the winding shaft.

The object of this invention is to produce an expansion unit readily mountable on a winding Shaft and having provision for securely holding a tubular core thereon. This unit eliminates all mechanical expanding and contracting means and can be built onto any shaft of reasonable size as a foundation. An important feature of the invention resides in the manner in which the unit obtains its grip on the core. Instead of relying solely on forcing grippers outwardly to engage the inner wall of the core the securement of the core to the shaft is, by this invention, effected by a slight distortion or deformation of the wall of the core which 'draws portions of it inward and into engagement with devices, normally disengaged, which thereupon grip the core to prevent relative rotary movement between it and the shaft during the winding operation. This is believed to be a new method of releasably binding a core on a winding shaft. Pneumatic pressure is the preferred means used to deform the wall of the core.

To the accomplishment of this object and such others as appear from the following disclosure, the invention comprises the features and combinations of parts hereinafter described and then particularly pointed out in the appended claims.

The nature and scope of the invention will best be understood from a description of its preferred embodiment. In the accompanying drawings:

Figure 1 is an end View of the air valve end of the shaft; Y

Fig. 2 is a side view of the shaft with a single core thereon but showing the core in section to disclose the expansion unit within it and also showing the air valve end of the unit in section;

Figs. 3 and 4 are cross-sectional views, taken through any length of core on the expansible unit, iirst showing the core loose on the shaft, and then gripped thereon;

Fig. 5 is a view of a portion of the shaft in longitudinal section through two of the pneumatic tubes and the air chamber, the air valve and its guard being omitted in this View; and

Fig. 6 is an outside view of the shaft showing a number of short cores carried by itsl expansion unit.

In the embodiment of the invention illustrated in the drawings the expansion unit is built upon a shaft I 0, conveniently steel tubing as illustrated to be driven from any convenient source of power for winding the web. The unit comprises a plurality of rubber tubes I2, four having been found to be effective, extending longitudinally of the shaft I0 and held in parallel positions at the outer face of said shaft by intermediate spacers or tube holders I4 having undercut ends so that the outer portion of each tube is effectively lapped at opposite sides by the ends of two adjacent spacers to hold it against the shaft yet leaving a sufcient opening between the spacers to permit an outward expansion of the tube between the spacers. Each spacer I4 is secured to the shaft I0 by a screw I6 and, taken as a unit, they form in effect a rigid cage for retaining the rubber tubes in angularly spaced relation along the shaft. The spacers I4 are preferably, although not necessarily, made of wood so that the cage may be of light weight.

Each wooden spacer supports a core v'gripper which may conveniently comprise a metal strip I8 secured in a recess in the spacer by a holding screw I6 and each provided with a marginal pair of edged fins I9 which project slightly from the circumferential surface of the tube cage. The diameter of the circle in which these core gripping ns lie will be substantially that of the inside diameter of the tubular core which is to be held in place on the shaft by means of the expansion unit of this invention. This relation of the parts is shown best by Fig. 3.

An air chamber abuts one end of the expansion unit and comprises a grooved collar 22 to be mounted on the shaft I0 with a running fit, the groove thereof being closed by a ring 24 having the joint soldered to make an air tight chamber. The inner wall of the air chamber thus provided is tapped, as illustrated, with four threaded holes 25 (see Fig. 1) each 90 apart tol be opposite the ends of the four rubber tubes l2. A hose nipple 26 (see Fig. 5) threaded at one end and slotted for receiving a screw driver at the other end is screwed into each tapped hole 25. The inner or air chamber ends of the rubber tubes are forced over these nipples and they may be tightly wound with` waxed thread to prevent leakage of air. It will be observed that the nipples serve to connect the air chamber to the expansion unit. A plug 21 of rubber, or other suitable material, has been squeezed into the free end of each rubber tube I2 this end then being wound with waxed thread to seal the joint. The air chamber and pneumatic tubes may be assembled first and placed loosely on the shaft and the tubes are then aligned and held against rotation on the shaft by securing the tube holders to the shaft between the tubes. Any manner of assembling the expansion unit "lay be employed that insures air tightness where the tubes communicate with the air chamber. Also spare tubes may be made up with the nipples pre-attached. A holding collar 28 of less diameter than the expansion unit may be removably set on the shaft I0 against the free ends of the rubber tubes and their spacers.

rIhe outer wall of the air chamber is tapped once for receiving an outwardly extending air valve 30. A valve guard 32 may be removably secured to the shaft IIJ by a set screw (see Fig. 2). If required, suitable bearing sleeves (not shown) may be set on the shaft I6 beyond the air valve guard at one end and beyond the collar 28, if used, at the other end.

The expansion unit is so designed that its diameter is not greater than that of the inside diameter of the tubular cardboard core 2l] on which winding or rewinding is to take place. After a core has been slipped over the expansion unit an air hose is attached to the air valve 36 and the tubes I2 are inflated. The expansion of the tubes outward through the space left between the tube holders at each side, as the tubes are inflated simultaneously, expands the core at four quadrantal points with a consequent slight distortion of its circular cross-section. The portions of the core wall intermediate the points of outward pressure become somewhat flattened. It will be remembered that the gripping fins I9 are located intermediate the pneumatic tubes so that the flattening of the core wall forces it against these iins. The inflation of the rubber tubes is continued until the flattening of the core wall opposite the fins has caused the fins to become sufficiently imbedded in the inner surface of the tubular core to effectually prevent any relative rotary movement between the core and the expansion unit or, essentially, the rotary shaft I9 which supports the expansion unit. This is illustrated by Fig. 4.

Deflation of the tubes l2 permits the core to resume its circular shape and, the grip of the ns being then released, the core and wound roll of paper or other material thereon may be slipped olf of the shaft and replaced by another core for another winding operation.

It is not essential that the core be as long as the expansion unit, that is, the unit is effective to grip a single core that is of less length than the length of the unit or to grip a plurality of short cores 4S of equal or of varying length as may be used in the rewinding mechanism of a paper slitter (see Fig. 6). The pneumatic tubes have walls heavy enough to withstand expansion between cores and to prevent injury to the ends of such short cores when expanded between them it being remembered that a comparatively slight expansion will deform the core wall suiiiciently to draw the core wall inward and on to the gripping fins.

While it is preferred to employ the specific construction and arrangement of parts shown and described it will be understood that this construction is not essential except so far as speciiied in the claims, and may be changed or modified without departing from the broader features of the invention.

The nature and scope of the invention having been indicated, and its preferred embodiment, operation and use having been specifically described, what is claimed as new, is:

l. A pneumatic winding shaft comprising a plurality of inflatable tubes laid loosely longitudinally of the shaft and held thereon in angularly spaced relation by intermediate tube holders secured to the shaft said holders having undercut edges adjacent the tubes within which said tubes are caged but with provision for outward expansion between pairs of holders, means carried by the shaft permitting inflation of said tubes whereby a tubular core slipped over the tubes is distended by said pressure along separated longitudinal areas and the areas in between are flattened, and core gripping devices on the shaft for biting into said flattened areas Y, of the core.

2. In combination, a shaft and an expansion unit mounted on said shaft for receiving a tubular winding core, said unit comprising a plurality of inflatable tubes extending loosely longitudinally of the shaft, tube holders secured to the shaft intermediate said tubes shaped to partially enclose each tube and core gripping devices intermediate said tube holders, the outside diameter of said unit when deflated being substantially that of the inside diameter of the core to be carried thereby, and means communicating with said tubes permitting inflation and causing expansion thereof from between the adjacent tube holders.

3. In combination, a shaft and an expansion unit adapted to hold a tubular winding core for rotation with the shaft, said unit comprising an air chamber on the shaft, a plurality of rubber tubes laid loosely longitudinally on said shaft each having one end secured to a port in said air chamber and the other end closed, tube holders secured to the shaft intermediate the tubes for maintaining the parallel relation of the tubes and lapping each tube at opposite sides to retain them against the shaft, fixed devices for biting into said core also intermediate the tubes, and means permitting inflation of the tubes to expand them outwardly between adjacent tub-e holders.

4. In combination with a cylindrical shaft, an annular air chamber on the shaft, a plurality of pneumatic tubes communicating therewith through one wall and extending loosely along the shaft, means on the shaft permitting inflation of said tubes from said air chamber, means secured to the shaft at each side of said tubes for spacing them and for holding them against the shaft while permitting expansion of the tubes therebetween, and xed `devices intermediate the tubes for gripping a tubular winding core adapted to be slipped over said assembly of tubes, spacers and grippers.

5. A pneumatic winding shaft comprising a plurality of inflatable tubes and a plurality of winding core gripping devices all extending longitudinally of the shaft and in alternating series about the shaft, means for securing the gripping devices to the shaft, tube holding strips also secured to the shaft at the opposite sides of each tube having their tube abutting edges shaped to partiallyv enclose a tube and retain it against the shaft, and means carried by the shaft and in communication with said tubes permitting inflation thereof and outward expansion between the adjacent holding strips.

6. A pneumatic winding shaft according to claim 5 in which a common means secures the core gripping devices and tube holders to the shaft.

'7. A pneumatic winding shaft according to claim 5 in which the tube holders fill the spaces between adjacent tubes and each supports a core gripping device.

8. A tubular cage for pneumatic winding shafts comprising a circular series of spaced tube holders, a circular series of inflatable tubes seated between Said holders, and a circular series of devices for biting into the winding core, one intermediate each pair of tubes.

9. A winding shaft having a removable external cage for holding a tubular core on the shaft for rotation therewith, said cage comprising pneumatic means for distending the wall of the core at angularly separated regions, and devices for biting into the core intermediate said regions onto vwhich said wall is drawn by its deformation.

l0. In a pneumatic winding shaft, an inner rotary shaft, a cage for removably` retaining a plurality of inflatable tubes longitudinally upon said rotary shaft comprising tube spacing strips secured to the rotary shaft between said tubes,

said strips having reversely undercut edge faces abutting the opposite sides of each tube providing a contracted opening through which an iniiated tube may expand to engage a winding core but may not escape, and devices intermediate the tubes for biting into a winding core slipped over the cage.

' 11. In a pneumatic winding shaft, an inner rotary shaft, a cage for removably retaining a plurality of inflatable tubes longitudinally upon said rotary shaft comprising tube spacing strips secured to the rotary shaft between said tubes, said strips havingv reversely undercut edge faces abutting the opposite sides of each tube providing a contracted opening through which an inflated tube may expand toengage a Winding core but may not escape, and edged ns supported by said tube spacing strips for biting into a Winding core slipped `over the cage.

12. In a pneumatic winding shaft, an inner rotary shaft, a cage for removably retaining a plurality of inflatable tubes longitudinally upon said rotary shaft comprising tube spacing strips secured to the rotary shaft between said tubes,v

said strips having reversely undercut'edge faces abutting the opposite sides of each tube providing a contracted opening through which an inflated tube may expand to engage a winding core but may not escape, penetrating core gripping devices A 

